Selective Metal-Site-Guided Arylation of Proteins

Abstract

We describe palladium-mediated S-arylation that exploits natural metal-binding motifs to ensure high site selectivity for a proximal reactive residue. This allows the chemical identification not only of proteins that bind metals but also the environment of the metal-binding site itself through proteomic analysis of arylation sites. The transformation is easy to perform under standard conditions, does not require the isolation of a reactive Ar-Pd complex, is broad in scope, and is applicable in cell lysates as well as to covalent inhibition/modulation of metal-dependent enzymatic activity.

Arylierungschemie für die Biokonjugation

“…[175] Füre in bekanntes Metalloenzym -M annosylglycerat-Synthase -z eigten sie, dass die Arylierung mit hoher Regioselektivitäta uf Cys-233 gelenkt werden konnte,das sich in der Nähe der endogenen, metallbindenden Struktur DxD befand, ohne dass dies Auswirkungen auf drei weitere Cysteinreste in demselben Protein [175] Füre in bekanntes Metalloenzym -M annosylglycerat-Synthase -z eigten sie, dass die Arylierung mit hoher Regioselektivitäta uf Cys-233 gelenkt werden konnte,das sich in der Nähe der endogenen, metallbindenden Struktur DxD befand, ohne dass dies Auswirkungen auf drei weitere Cysteinreste in demselben Protein …”

Metallvermittelte Funktionalisierung natürlicher Peptide und Proteine: Biokonjugation mit Übergangsmetallen

“…[75] Viele Enzyme verfügen über Cysteinseitenketten in ihrem aktiven Zentrum. [75] Viele Enzyme verfügen über Cysteinseitenketten in ihrem aktiven Zentrum.…”

Transition Metal-Promoted Arylation: An Emerging Strategy for Protein Bioconjugation

“…[15] Another powerful approach to palladium-mediated Cys arylation was recently reported in 2016 by Davis and coworkers. [16] This method exploits the endogenous metal binding motifs often displayed in the active sites of metal-dependent enzymes to direct regioselective palladium-catalyzed S-arylation in the presence of multiple Cys residues. The authors hypothesized that a native binding site might serve to guide a reactive metal complex, which could then covalently modify a proximal reactive Cys residue (Fig.…”

“…Davis and coworkers went on to demonstrate selective palladium-mediated S-arylation of MGS using a broad range of substituted aryl iodides, including isotope labels, carbohydrates, and functional handles for bioconjugation. [16] Given the proximity of most metal-binding sites (and therefore the Cys residues modified by the guided S-arylation protocol) to the enzyme active site, the authors also evaluated select S-aryl constructs as covalent modulators of MGS enzymic activity. These studies provided proof of concept for the design of metalpromoted, active site-directed covalent inhibition of enzyme targets.…”

“…As a general tool, proteomic analysis of S-arylation sites can provide valuable insight into the environment surrounding metal-binding motifs. [16] Transition metal-mediated arylations of Cys, including the two described above, rely on the nucleophilicity of the side chain thiol at physiological pH. Selenocysteine (Sec), the selenium analogue of Cys and so-called 21st proteinogenic amino acid, [17] also displays potent nucleophilicity at physiological pH, at which its acidity (pK a 5.47) [18] renders it primarily in the anionic selenolate form.…”